Seismic Response of Nonstructural Components Supported on Piers and Wharves

This paper presents the results of a parametric study performed to investigate the seismic response of nonstructural components such as marine loading arms and gangway towers supported on pier and wharf structures. The existing seismic code provisions have included empirical equations for calculating an effective seismic force for nonstructural components which are more applicable to a multi-story building than to a waterfront structure. Moreover, the empirical equations do not account for the inelasticity of the supporting structure. To study the seismic interaction between a nonstructural component and a supporting pier structure, time history analyses are conducted using a set of twenty-eight ground motions at different performance levels. Nonstructural components considered in this study can be idealized as a single-degree-of freedom system, and their seismic mass is small compared to the total mass of the supporting pier structure. This paper reviews the influence of key parameters that affect the seismic response of the nonstructural component, such as the ratio of the time periods of the component and the supporting pier structure, the effective damping of the component and the effective damping of the supporting structure. A comparison between the results of this parametric study and the code-based empirical equations is also presented.